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77251e41f8
When a crypto template needs to be instantiated, CRYPTO_MSG_ALG_REQUEST is sent to crypto_chain. cryptomgr_schedule_probe() handles this by starting a thread to instantiate the template, then waiting for this thread to complete via crypto_larval::completion. This can deadlock because instantiating the template may require loading modules, and this (apparently depending on userspace) may need to wait for the crc-t10dif module (lib/crc-t10dif.c) to be loaded. But crc-t10dif's module_init function uses crypto_register_notifier() and therefore takes crypto_chain.rwsem for write. That can't proceed until the notifier callback has finished, as it holds this semaphore for read. Fix this by removing the wait on crypto_larval::completion from within cryptomgr_schedule_probe(). It's actually unnecessary because crypto_alg_mod_lookup() calls crypto_larval_wait() itself after sending CRYPTO_MSG_ALG_REQUEST. This only actually became a problem in v4.20 due to commitb76377543b
("crc-t10dif: Pick better transform if one becomes available"), but the unnecessary wait was much older. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=207159 Reported-by: Mike Gerow <gerow@google.com> Fixes:398710379f
("crypto: algapi - Move larval completion into algboss") Cc: <stable@vger.kernel.org> # v3.6+ Cc: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Reported-by: Kai Lüke <kai@kinvolk.io> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
293 lines
5.9 KiB
C
293 lines
5.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Create default crypto algorithm instances.
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*
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* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
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*/
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#include <crypto/internal/aead.h>
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#include <linux/completion.h>
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#include <linux/ctype.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kthread.h>
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#include <linux/module.h>
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#include <linux/notifier.h>
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#include <linux/rtnetlink.h>
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#include <linux/sched/signal.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include "internal.h"
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struct cryptomgr_param {
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struct rtattr *tb[CRYPTO_MAX_ATTRS + 2];
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struct {
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struct rtattr attr;
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struct crypto_attr_type data;
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} type;
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union {
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struct rtattr attr;
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struct {
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struct rtattr attr;
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struct crypto_attr_alg data;
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} alg;
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struct {
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struct rtattr attr;
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struct crypto_attr_u32 data;
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} nu32;
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} attrs[CRYPTO_MAX_ATTRS];
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char template[CRYPTO_MAX_ALG_NAME];
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struct crypto_larval *larval;
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u32 otype;
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u32 omask;
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};
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struct crypto_test_param {
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char driver[CRYPTO_MAX_ALG_NAME];
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char alg[CRYPTO_MAX_ALG_NAME];
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u32 type;
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};
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static int cryptomgr_probe(void *data)
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{
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struct cryptomgr_param *param = data;
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struct crypto_template *tmpl;
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int err;
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tmpl = crypto_lookup_template(param->template);
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if (!tmpl)
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goto out;
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do {
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err = tmpl->create(tmpl, param->tb);
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} while (err == -EAGAIN && !signal_pending(current));
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crypto_tmpl_put(tmpl);
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out:
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complete_all(¶m->larval->completion);
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crypto_alg_put(¶m->larval->alg);
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kfree(param);
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module_put_and_exit(0);
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}
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static int cryptomgr_schedule_probe(struct crypto_larval *larval)
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{
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struct task_struct *thread;
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struct cryptomgr_param *param;
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const char *name = larval->alg.cra_name;
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const char *p;
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unsigned int len;
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int i;
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if (!try_module_get(THIS_MODULE))
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goto err;
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param = kzalloc(sizeof(*param), GFP_KERNEL);
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if (!param)
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goto err_put_module;
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for (p = name; isalnum(*p) || *p == '-' || *p == '_'; p++)
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;
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len = p - name;
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if (!len || *p != '(')
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goto err_free_param;
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memcpy(param->template, name, len);
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i = 0;
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for (;;) {
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int notnum = 0;
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name = ++p;
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for (; isalnum(*p) || *p == '-' || *p == '_'; p++)
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notnum |= !isdigit(*p);
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if (*p == '(') {
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int recursion = 0;
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for (;;) {
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if (!*++p)
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goto err_free_param;
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if (*p == '(')
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recursion++;
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else if (*p == ')' && !recursion--)
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break;
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}
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notnum = 1;
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p++;
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}
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len = p - name;
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if (!len)
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goto err_free_param;
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if (notnum) {
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param->attrs[i].alg.attr.rta_len =
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sizeof(param->attrs[i].alg);
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param->attrs[i].alg.attr.rta_type = CRYPTOA_ALG;
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memcpy(param->attrs[i].alg.data.name, name, len);
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} else {
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param->attrs[i].nu32.attr.rta_len =
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sizeof(param->attrs[i].nu32);
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param->attrs[i].nu32.attr.rta_type = CRYPTOA_U32;
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param->attrs[i].nu32.data.num =
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simple_strtol(name, NULL, 0);
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}
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param->tb[i + 1] = ¶m->attrs[i].attr;
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i++;
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if (i >= CRYPTO_MAX_ATTRS)
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goto err_free_param;
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if (*p == ')')
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break;
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if (*p != ',')
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goto err_free_param;
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}
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if (!i)
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goto err_free_param;
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param->tb[i + 1] = NULL;
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param->type.attr.rta_len = sizeof(param->type);
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param->type.attr.rta_type = CRYPTOA_TYPE;
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param->type.data.type = larval->alg.cra_flags & ~CRYPTO_ALG_TESTED;
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param->type.data.mask = larval->mask & ~CRYPTO_ALG_TESTED;
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param->tb[0] = ¶m->type.attr;
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param->otype = larval->alg.cra_flags;
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param->omask = larval->mask;
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crypto_alg_get(&larval->alg);
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param->larval = larval;
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thread = kthread_run(cryptomgr_probe, param, "cryptomgr_probe");
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if (IS_ERR(thread))
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goto err_put_larval;
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return NOTIFY_STOP;
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err_put_larval:
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crypto_alg_put(&larval->alg);
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err_free_param:
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kfree(param);
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err_put_module:
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module_put(THIS_MODULE);
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err:
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return NOTIFY_OK;
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}
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static int cryptomgr_test(void *data)
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{
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struct crypto_test_param *param = data;
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u32 type = param->type;
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int err = 0;
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#ifdef CONFIG_CRYPTO_MANAGER_DISABLE_TESTS
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goto skiptest;
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#endif
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if (type & CRYPTO_ALG_TESTED)
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goto skiptest;
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err = alg_test(param->driver, param->alg, type, CRYPTO_ALG_TESTED);
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skiptest:
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crypto_alg_tested(param->driver, err);
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kfree(param);
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module_put_and_exit(0);
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}
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static int cryptomgr_schedule_test(struct crypto_alg *alg)
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{
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struct task_struct *thread;
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struct crypto_test_param *param;
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u32 type;
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if (!try_module_get(THIS_MODULE))
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goto err;
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param = kzalloc(sizeof(*param), GFP_KERNEL);
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if (!param)
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goto err_put_module;
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memcpy(param->driver, alg->cra_driver_name, sizeof(param->driver));
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memcpy(param->alg, alg->cra_name, sizeof(param->alg));
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type = alg->cra_flags;
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/* Do not test internal algorithms. */
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if (type & CRYPTO_ALG_INTERNAL)
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type |= CRYPTO_ALG_TESTED;
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param->type = type;
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thread = kthread_run(cryptomgr_test, param, "cryptomgr_test");
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if (IS_ERR(thread))
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goto err_free_param;
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return NOTIFY_STOP;
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err_free_param:
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kfree(param);
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err_put_module:
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module_put(THIS_MODULE);
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err:
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return NOTIFY_OK;
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}
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static int cryptomgr_notify(struct notifier_block *this, unsigned long msg,
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void *data)
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{
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switch (msg) {
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case CRYPTO_MSG_ALG_REQUEST:
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return cryptomgr_schedule_probe(data);
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case CRYPTO_MSG_ALG_REGISTER:
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return cryptomgr_schedule_test(data);
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case CRYPTO_MSG_ALG_LOADED:
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break;
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}
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return NOTIFY_DONE;
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}
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static struct notifier_block cryptomgr_notifier = {
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.notifier_call = cryptomgr_notify,
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};
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static int __init cryptomgr_init(void)
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{
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return crypto_register_notifier(&cryptomgr_notifier);
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}
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static void __exit cryptomgr_exit(void)
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{
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int err = crypto_unregister_notifier(&cryptomgr_notifier);
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BUG_ON(err);
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}
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/*
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* This is arch_initcall() so that the crypto self-tests are run on algorithms
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* registered early by subsys_initcall(). subsys_initcall() is needed for
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* generic implementations so that they're available for comparison tests when
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* other implementations are registered later by module_init().
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*/
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arch_initcall(cryptomgr_init);
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module_exit(cryptomgr_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Crypto Algorithm Manager");
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